Yes, $100K was a relatively small sum -- but the company that owned the rights was going bankrupt, and Blender was going to die.

For a lucrative game, a reasonable value would be 2 to 4 years of earnings.

For example: if the product makes $10K/month:

    $10k × 36 (a mid-range multiple) = $360,000

With this amount, the author would have at least 3 years of headway, with a much larger open source community.